Can pesticide mixing harm the health, behavior and reproduction of native solitary bees?

Abstract

Fragmentation, climate change and the presence of xenobiotics in the environment, especially pesticides, have threatened bee species worldwide. Studies are currently focused on evaluating the effects of these stressors on Apis mellifera, but bees have a wide variety of habits that may not be represented by a single model species. In addition, most species have solitary habits. This study aims to evaluate the sublethal effects of exposure to two pesticides on the Centris solitary bee under semi-field and in vitro conditions. In semi-field conditions, cages will be installed containing plants treated with the acetamipride neonicotinoid, the azoxystrobin fungicide, both pesticides or neither, so that the bees can be exposed orally or by contact. The effects of these pesticide exposures on survival and mortality, nesting rate, sex ratio and foraging behavior of floral resources will be evaluated. Moreover, in bees exposed to acetamipride these same effects will be evaluated in the second generation. Under in vitro conditions, bees will be exposed to the same pesticides at concentrations that reach non-target drift plants and at concentrations that reach target plants. Sublethal effects on the gut, brain and ovary of these bees as well as on survival will be evaluated. This is the first paper to propose a standardization of methodology for the evaluation of realistic dose effects of pesticides in C. anal and the second generation of this Brazilian native solitary bee. (AU)